The Expanding Role of Echocardiography in Patients with Heart Failure

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Citation
US Cardiology 2004;2004:1(1):53-56

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A patient presents to their physician with progressive dyspnea on exertion, orthopnea, and fatigue. Physical examination reveals bibasal rales, distended neck veins, an S3 gallop, and an apical holo-systolic murmur. The clinical diagnosis is straightforward - this patient has congestive heart failure.Almost certainly one of the first tests performed in this patientÔÇÖs diagnostic evaluation will be an echocardiogram. Indeed, echocardiography is routinely used in patients with heart failure to answer the following clinical questions:

  • Is the problem purely one of ventricular performance or is there other underlying pathology such as congenital heart disease or primary valve disease?
  • Is there systolic dysfunction and, if so, what is the ejection fraction?

Providing the answers to these questions is basic echocardiography. However, as will be expanded on in this review, the technique is capable of providing much more. Specifically, a comprehensive echocardiographic evaluation of the patient with heart failure can and should include a detailed assessment of cardiac anatomy, right and left ventricular systolic and diastolic function, valvular function, particularly that of the atrioventricular valves, and in some cases, determination of hemodynamic parameters such as cardiac output and filling pressures.

This information may be integrated to provide prognostic information and guide therapy, the latter being particularly important in patients with QRS prolongation in whom cardiac resynchronization therapy (biventricular pacing) may be an option. Finally, although not directly relevant to the clinician, it is notable that current echocardiographic techniques provide an experimental tool in small animal models of heart failure.

Anatomy

A delineation of cardiac anatomy is an important part of the evaluation of the patient with heart failure. After excluding underlying congenital heart disease or primary valve disease, the echocardiographic evaluation quickly focuses on both ventricles and the atrioventricular valves. The exquisite spatial resolution of echocardiography, its multiple imaging windows and more recently introduced three-dimensional (3-D) applications provide precise methods of assessing ventricular volumes, planar dimensions, left ventricular mass, and wall thickness.

These techniques may be applied to the right ventricle as well as to the left ventricle. Echocardiography has also been important in identifying mitral and tricuspid annular dilation and the left ventricular geometric alterations that cause functional mitral and tricuspid regurgitation. It may also identify complications such as intra-cavitary thrombus.

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References
  1. A full discussion of these techniques is beyond the scope of this article and the reader is referred to an excellent review on the subject by Nagueh, et al., in the American College of Cardiology Current Journal Review (Jan/Feb 2002).